1. Field
The present disclosure relates generally to electrosurgical systems and, more specifically, to a system for delivering high power radiofrequency energy using multiple resonant inductor-capacitor (LC) networks.
2. Description of the Related Art
Electrosurgery involves application of high radio frequency (RF) electrical energy to a surgical site to cut, ablate, or coagulate tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of the surgical instrument held by the surgeon and applied to the tissue to be treated. A patient return electrode is placed remotely from the active electrode to carry the current back to the generator.
Ablation is a monopolar procedure which is particularly useful in the field of neurosurgery, where one or more RF ablation needle electrodes (usually of elongated cylindrical geometry) are inserted into a living body. A typical form of such needle electrodes incorporates an insulated sheath from which an exposed (uninsulated) tip extends. When an RF voltage is provided between the reference electrode and the inserted ablation electrode, RF current flows from the needle electrode through the body. Typically, the current density is very high near the tip of the needle electrode, which heats and destroys the adjacent tissue.
In bipolar electrosurgery, one of the electrodes of the hand-held instrument functions as the active electrode and the other as the return electrode. The return electrode is placed in close proximity to the active (current supplying) electrode such that an electrical circuit is formed between the two electrodes (e.g., electrosurgical forceps). In this manner, the applied electrical current is limited to the body tissue positioned between the electrodes. When the electrodes are sufficiently separated from one another, the electrical circuit is open and thus inadvertent contact of body tissue with either of the separated electrodes does not cause current to flow.
In electrosurgery, RF energy must be generated having sufficient frequency, so that the RF energy may be used to cut, coagulate, etc., tissue by sustaining tissue thermal heating for prolonged periods of time. Current state of the art electrosurgical generators do not provide sufficiently powerful RF energy for prescribed periods of time or they do so in an inefficient manner. Therefore there is a need for an electrosurgical generator which can generate high amounts electrosurgical energy in an efficient manner.